Beneficial or not, apple cider vinegar is still an acid, and it can be rough on your insides.

I'll never forget the time I ate way too much pineapple, causing the inside of my mouth to feel like I'd put it through a paper shredder. Thanks, natural acids.

It turns out that drinking straight, undiluted ACV is similarly dangerous to your insides — from your mouth on down.

"Never drink vinegar straight. It is a potent acid that can be dangerous if aspirated, may cause burns to the tender tissue of the mouth and esophagus, and can lead to tooth erosion," registered dietitian and Food Network personality Ellie Krieger wrote for the Washington Post.

Krieger isn't alone in warning about the potential health risks of too much ACV.

"One of the big downsides of ACV is that it may cause nausea and other gastrointestinal symptoms, so if you already have [a] sensitive tummy, it may not be for you," registered dietitian Abbey Sharp told Global News.

Of course, that isn't to say you should avoid ACV altogether. It's just not a good idea to make sure you're consuming it in a way that's safe for your body.

Registered dietitian and certified diabetes educator Franziska Spritzler drew my attention to this case of an otherwise healthy 28-year-old woman who developed both low potassium and osteoporosis. Doctors treating her credited both to the patient's over-the-top ACV habit.

Over the course of six years, the patient drank 8 ounces (250 ml) of ACV per day, both diluted in water and mixed into homemade salad dressing recipes.

In most healthy people, the Mayo Clinic says it's rare to see serious symptoms due to low potassium. However, abnormal heart rhythms (arrhythmias) are definite signs you should see your doctor — particularly if you've previously been diagnosed with heart disease.

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ACV can also interact negatively with certain doctor-prescribed medications.

ACV isn't always a good combination with certain medications.
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If you take insulin, digoxin (lanoxin), or certain diuretic drugs, ACV can amplify the potassium-lowering effects those medications already have, Spritzler warns.

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There’s no scientific evidence that ACV can help you lose significant amounts of weight on its own.

Hopeful articles and books touting ACV's alleged weight loss benefits often cite a single scientific study published in 2009 in the scholarly journal "Bioscience, Biotechnology, Biochemistry."

The study found that participants in the group who were given ACV did lose more weight than those given a placebo over a 12-week period. However, the weight loss amount — two to four pounds — was quite small. Also, the study didn't include details about the participants' diet and exercise habits.

"Vinegar is not a magic bullet for weight loss," Dr. Carol S. Johnston, professor and associate director of the nutrition program at Arizona State University, told the Washington Post.

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Eating an actual apple is better for nutritional purposes.

Just eat an apple.
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If you're considering adding ACV to your daily routine for any of the following, you might want to think again:

ACV might be able to help control blood sugar.

Dr. Johnston has been studying the effects of vinegar on health for over 10 years. According to one study she conducted, it appears that vinegar can help to control blood sugar. It does this by inhibiting the enzymes that allow you to digest starches.

However, Spritzler warns that this delayed stomach emptying effect— which is caused by slowing down your starch digestion — can actually make blood sugar control more difficult for type 1 diabetics.

ACV could also help regulate cholesterol levels.

BBC Magazine teamed up with Dr. James Brown — senior lecturer at the School of Life and Health Sciences at Aston University — to run a few experiments of their own.

30 healthy adult volunteers participated in the testing. They were divided into three groups. Group 1 drank two tablespoons of ACV diluted in 200 ml of water twice daily. The second group did the same thing, only with malt vinegar in place of ACV. The third group was given a watery placebo with some food color.

After two months, the volunteers were called back for testing. The conclusions?

No weight loss. No scientifically observable anti-inflammatory properties. But they did notice something about cholesterol levels.

On average, the 10 study participants who took the prescribed dose of diluted ACV daily saw an average 13% reduction in total cholesterol levels. Not only that — levels of triglycerides (a kind of fat) went down too, although the BBC piece does not reveal exact numbers.

All volunteers participating in this study began with completely normal cholesterol levels.

"Bringing cholesterol levels down like this can significantly reduce your chances of having a heart attack in the future. So we were really excited to see that finding," said Dr. Brown.

It's worth noting that this was a very small group, and not a peer-reviewed study. Additional research should be done before reaching any conclusions, but it's hard not to see this result as encouraging.